The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Recently, as portable wireless terminals have been increasingly popularized, users need additional functions to their tastes even in opening and closing operations of the terminal, along with its inherent functions of wireless communications.
In response to these needs, portable terminals have developed into a bar type, flip type, flip-up type, folder type, and the like. In recent years, the folder type has been used most widely. This is because the folder type terminal has a space sufficient enough to accommodate a wide LCD module as its display device and can be carried in a folded state to thereby provide a good portability, as compared with other types of terminals.
In more recent years, a slider type terminal has been introduced, which can be equipped with an LCD module display device having a similar size to the folder type. Simultaneously, the slider mechanism thereof can contribute to miniaturization of portable terminals.
This slider type terminal is structured such that a sub-body corresponding to a cover is slidably opened and closed on a main body, thereby providing additional advantages of slidably opening and closing, while maintaining the merits of the existing folder type terminal.
For example, Korean Utility Model Registration No. 0308165 discloses a slider-type portable wireless terminal. The terminal disclosed in the above application includes a guide means for guiding a slider body on a main body and at least one resilient means installed between the slider body and the main body such that its resilient force can be exerted in opening or closing direction with respect to a certain sliding point of the slider body. In addition, when the slider body is completely opened or closed, it can remain in its opened or closed state due to the resilient means, without any separate stopper. The resilient means employs a torsion spring, one end portion of which is fixed to the main body and the other end thereof is fixed to the slider body.
In this slider mechanism, the torsion spring must exert resiliency to the slider body over the whole range of traveling, and the torsion spring is to be compressed and restored repeatedly over a wide range of amplitude. Therefore, a torsion spring expandable over a wide length is used, but this torsion spring has a smaller resilient force. In order to compensate for the deficient resilient force, two torsion springs are employed.
But the torsion spring is compressed and restored in a wide range and thus easily aged due to fatigue caused by the repeated operations. Consequently, the torsion spring comes to lose its normal function or leads to an earlier failure.
In addition, this type of slider mechanism needs at least two torsion springs and further each torsion spring requires at least two windings, for the purpose of desired opening and closing operations. It should be noted here that the space between the main body and the slider body varies with the diameter of spring wire and the number of windings of the torsion spring. That is, as the wire diameter increases and/or the winding numbers increases, the spacing between the main body and the slider body is inevitably widened. For example, in case where the torsion spring has a wire diameter of 0.5 millimeters and two windings, the spacing between the main body and the slider body must be 1.0 millimeter at minimum. Consequently, the portable terminal becomes bulky and thus its portability becomes worse.
Furthermore, in case of this type of slider mechanism using a torsion spring, the elastic force varies with the angle of the torsion spring. Thus, it is not easy to control the sliding force formed between the main body and the slider body. That is, the portable terminal itself may receive impact and thus the service life thereof will be shortened if any separate impact absorber or the like is not provided.